In several old questions/answers I have seen in MathJax the combination
\\, where it obviously should be
\, and also
\* where it should be just
* - the result is a badly distorted formula, torn into confusingly displaced pieces in the first case, and just a red $\*$ in the second case.
I have just corrected it for https://mathoverflow.net/a/104701/41291, and I have done this at least twice before, so I now suspect there might be some bug doing this.
On the other hand this seemingly only occurs in relatively old posts, so maybe there was a bug which is extinguished by now.
Is this a known issue?